Pre-oxidizing high-dielectric-constant material electrodes

ABSTRACT

Generally, according to the present invention, the sidewall of the adhesion layer (e.g. TiN 36) in a lower electrode is pre-oxidized after deposition of an unreactive noble metal layer (e.g. Pt 38) but before deposition of an HDC material (e.g. BST 42). An important aspect of the present invention is that the pre-oxidation of the sidewall generally causes a substantial amount of the potential sidewall expansion (and consequent noble metal layer deformation) to occur before deposition of the HDC material. One embodiment of the present invention is a microelectronic structure comprising a supporting layer having a principal surface, and an adhesion layer overlying the principal surface of the supporting layer, wherein the adhesion layer comprises a top surface and an expanded, oxidized sidewall (e.g. TiO 2  40). The structure further comprises a noble metal layer overlying the top surface of the adhesion layer, wherein the noble metal layer comprises a deformed area overlying the oxidized sidewall, and a high-dielectric-constant material layer overlying the noble metal layer. The high-dielectric-constant material layer is substantially free of expansion stress cracks in proximity to the deformed area of the noble metal layer.

This is a divisional of application Ser. No. 08/283,467 filed Aug. 1,1994.

CROSS-REFERENCES TO RELATED APPLICATIONS

The following related applications were filed concurrently with theinstant application:

    __________________________________________________________________________    Title                       Inventors                                                                            Ser. No.                                   __________________________________________________________________________    Improved High-Dielectric-Constant Material Electrodes                                                     Summerfelt,                                                                          08/283,881                                 Comprising Thin Platinum Layers                                                                           Beratan,                                                                      Kirlin,                                                                       Gnade                                             Improved Electrodes Comprising Conductive Perovskite-                                                     Summerfelt,                                                                          08/283,468                                 Seed Layers for Perovskite Dielectrics                                                                    Beratan                                           Improved High-Dielectric-Constant Material Electrodes                                                     Summerfelt,                                                                          08/283,442                                 Comprising Thin Ruthenium Dioxide Layers                                                                  Beratan,                                                                      Kirlin,                                                                       Gnade                                             High-Dielectric-Constant Material Electrodes Comprising                                                   Nishioka,                                                                            08/283,871                                 Sidewall Spacers            Park,                                                                         Bhattacharya,                                                                 Summerfelt                                        A Conductive Amorphous-Nitride Barrier Layer for High-                                                    Summerfelt                                                                           08/293,441                                 Dielectric-Constant Material Electrodes                                       A Conductive Exotic-Nitride Barrier Layer for High-                                                       Summerfelt                                                                           08/283,873                                 Dielectric-Constant Material Electrodes                                       A Conductive Noble-Metal-Insulator-Alloy Barrier Layer                                                    Summerfelt,                                                                          08/283,454                                 for High-Dielectric-Constant Material Electrodes                                                          Nicolet,                                                                      Reid,                                                                         Kolawa                                            __________________________________________________________________________

The following previously filed applications are related to the instantapplication:

    __________________________________________________________________________                                       U.S. Pat.                                  Title                       Inventors                                                                            Ser. No                                    __________________________________________________________________________    Improved Electrical Connections to Dielectric Materials                                                   Gnade, U.S.                                                                   Summerfelt                                                                           5,348,894                                  Improved Electrical Connections to Dielectric Materials                                                   Gnade, 08/260,149                                                             Summerfelt                                        Lightly Donor Doped Electrodes for High-Dielectric-                                                       Summerfelt,                                                                          08/040,946                                 Constant Materials          Beratan,                                                                      Gnade                                             Lightly Donor Doped Electrodes for High-Dielectric-                                                       Summerfelt,                                                                          08/276,191                                 Constant Materials          Beratan,                                                                      Gnade                                             Improved Electrode Interface for High-Dielectric-Constant                                                 Summerfelt,                                                                          08/041,025                                 Materials                   Beratan                                           __________________________________________________________________________

FIELD OF THE INVENTION

This invention generally relates to improving electrical connections tomaterials with high-dielectric-constants, such as in the construction ofcapacitors.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with current methods of forming electrical connections tohigh-dielectric-constant materials, as an example.

The increasing density of integrated circuits (e.g. DRAMs) is increasingthe need for materials with high-dielectric-constants to be used inelectrical devices such as capacitors. Generally, capacitance isdirectly related to the surface area of the electrode in contact withthe capacitor dielectric, but is not significantly affected by theelectrode volume. The current method generally utilized to achievehigher capacitance per unit area is to increase the surface area unitarea by increasing the topography, such as in trench and stackcapacitors using SiO₂ or SiO₂ /Si₃ N₄ as the dielectric. This approachbecomes very difficult in terms of manufacturability for devices such asthe 256 Mbit and 1 Gbit DRAMs.

An alternative approach is to use a high permittivity dielectricmaterial. Many perovskite, ferroelectric, or high-dielectric-constant(hereafter abbreviated HDC) materials such as (Ba,Sr)TiO₃ (BST) usuallyhave much larger capacitance densities than standard SiO₂ --Si₃ N₄--SiO₂ capacitors. Various metals and metallic compounds, and typicallynoble metals such as Pt and conductive oxides such as RuO₂, have beenproposed as the electrodes for these HDC materials. To be useful inelectronic devices, however, reliable electrical connections shouldgenerally be constructed which do not diminish the beneficial propertiesof these high-dielectric-constant materials.

SUMMARY OF THE INVENTION

As used herein, the term "high-dielectric-constant" means a dielectricconstant greater than about 50 at device operating temperature. Thedeposition of an HDC material usually occurs at high temperature(generally greater than about 500° C.) in an oxygen containingatmosphere. Many electrode materials oxidize and become insulating orotherwise degrade in this type of environment. An initial electrodestructure formed prior to the HDC material deposition should be stableboth during and after this deposition, while subsequent electrodestructures formed after this deposition need only be stable after thisdeposition.

As mentioned hereinabove, Pt has been suggested for the electrodes of anHDC material layer in standard thin-film (herein defined as generallyless than 5 microns (um)) applications. However, although Pt isunreactive with respect to the HDC material, it has been found that itis difficult to use Pt alone as an initial electrode. Pt generallyallows oxygen to diffuse through it and hence typically allowsneighboring materials to oxidize. In addition, Pt also does not normallystick very well to traditional dielectrics such as SiO₂ or Si₃ N₄, andPt can rapidly form a silicide at low temperatures. Thus a Ta or TiNlayer has been suggested as an adhesion or buffer layer under the Ptelectrode. However, during BST deposition or annealing, oxygen canpossibly diffuse through the Pt and oxidize the adhesion layer and makethe adhesion layer less conductive. This may be more of a problem on thesides of the adhesion layer than on the top horizontal surface, sincethe Pt will generally be thicker on the top, and a better diffusionbarrier.

Conductive oxides such as RuO₂ have also been suggested for theelectrodes of an HDC material layer in standard thin-film applications.Again, although RuO₂ is unreactive with respect to the HDC material, ittoo generally has difficulties. For example, the electrical propertiesof the structures formed using these oxides are usually inferior tothose formed using e.g. Pt. Many thin-film applications require a smallleakage-current-density in addition to a large capacitance per unitarea. The leakage current is sensitive to many variables such asthickness, microstructure, electrodes, electrode geometry andcomposition. For example, the leakage current of lead zirconium titanate(PZT) using RuO₂ electrodes is several orders of magnitude larger thanthe leakage current of PZT using Pt electrodes. In particular it appearsthat the leakage current is controlled by Schottky barriers, and thatthe smaller leakage current with Pt electrodes appears to be due to thelarger work function.

As used herein, the term "unreactive", when used in reference to amaterial contacting an HDC material, means a material which provides astable conductive interface to the HDC material during and afterprocessing. Note that when a conductive oxide such as RuO₂ is used forthe unreactive layer (or another part of the electrode), that layer canalso contain unoxidized or partially oxidized Ru. For example, anunreactive layer of Ru which is chemically changed by becoming partiallyor fully oxidized during the HDC deposition process is still consideredunreactive since it still provides a stable conductive interface to theHDC material.

Other structures which have been proposed for standard thin-filmstructures include alloys of Pt, Pd, Rh as the electrode and oxides madeof Re, Os, Rh and Ir as a sticking layer on single crystal Si orpoly-Si. A problem with these electrodes is that these oxides areusually not stable next to Si and that these metals typically rapidlyform silicides at low temperatures (generally less than about 450° C).If other associated problems can be avoided or minimized, this type ofelectrode structure should retain its conductivity even after thedeposition of the HDC material if an appropriate adhesion (barrier)layer(s) is used between the conductive oxide and the Si substrate.

Thus many of the proposed lower electrode structures comprise thefollowing generic layers: HDC material/unreactive (oxygen stablelayer/adhesion (barrier) layer/substrate. In these structures, theadhesion layer typically comprises a conductive material that oxidizeunder HDC material deposition conditions to provide a conductive oxide.It has been discovered that expansion stress and crack formation in theHDC material can occur due to the oxidizing and consequent expanding ofthe adhesion layer during HDC material deposition.

Although this oxidation/expansion can generally occur at any surface ofthe adhesion layer, oxidation of the top of the adhesion layer issubstantially impeded by the overlying unreactive layer, and oxidationof the bottom of the adhesion layer is substantially impeded by thematerial surrounding it (e.g. the substrate). Generally, an exposedsidewall would be the most likely surface of the adhesion layer to beoxidized. Since most materials proposed for the adhesion layerexperience a volume change when oxidized, the adhesion layer sidewallgenerally expands and deforms the overlying unreactive layer and causesstress and cracking of the HDC material layer. These cracks can reachfrom the upper surface of the HDC material layer down to the lowerelectrode, with detrimental results. For example, if a conductive layer,such as an upper electrode for a capacitor, is deposited on the HDClayer, the capacitor can have substantial leakage or even be shortedbetween the two electrodes.

Generally, according to the present invention, the sidewall of theadhesion layer is pre-oxidized before deposition of the HDC material(but after deposition of an unreactive noble metal layers. An importantaspect of the present invention is that the pre-oxidation of thesidewall generally causes a substantial mount of the potential sidewallexpansion and consequent noble metal layer deformation to occur beforedeposition of the HDC material. Potential sidewall expansion is definedas the total amount of expansion that occurs through HDC deposition andannealing (with or without pre-oxidation.

According to the present invention, the sidewall of the adhesion layeris substantially oxidized before HDC deposition. In contrast to thepresent invention, superficial oxidation (e.g. forming a few monolayersof oxide) at various stages of fabrication of a ferroelectric capacitorhas apparently been described in the prior art. See European PatentApplication 557,937 A1, D. Patel et al., Ramtron International Corp.,filed Feb. 23, 1993. The oxidation described by D. Patel et al. issuperficial and is apparently in a different portion of the structureand for a different purpose, i.e., better adhesion to the bottom glasslayer and to the top ferroelectric material, than the present invention.The adhesion layer sidewall of the present invention must generally bemore than merely superficially oxidized, since a superficially oxidizedadhesion layer would generally still undergo substantial oxidation andexpansion during HDC deposition, to the detriment of the structure.

One embodiment of the present invention is a microelectronic structurecomprising a supporting layer having a principal surface, and anadhesion layer overlying the principal surface of the supporting layer,wherein the adhesion layer comprises a top surface and an expanded,oxidized sidewall. The structure further comprises a noble metal layeroverlying the top surface of the adhesion layer, wherein the noble metallayer comprises a deformed area overlying the oxidized sidewall, and ahigh-dielectric-constant material layer overlying the noble metal layer.The high-dielectric-constant material layer is substantially free ofexpansion stress cracks in proximity to the deformed area of the noblemetal layer.

A method of forming an embodiment of the present invention comprisesforming a supporting layer having a principal surface, forming anadhesion layer on the principal surface of the supporting layer, andforming a noble metal layer on a top surface of the adhesion layer,wherein the adhesion layer comprises a substantially unoxidizedsidewall. The method further comprises oxidizing the unoxidized sidewallof the adhesion layer to form a pre-oxidized sidewall, and depositing ahigh-dielectric-constant material layer on the noble metal layer. Thepreoxidized sidewall minimizes further oxidation and expansion of theadhesion layer adjacent the pre-oxidized sidewall. Expansion stress andcracking of the high-dielectric-constant material layer is minimizedduring the step of depositing the high-dielectric-constant materiallayer.

These are apparently the first microelectronic structures wherein anelectrode to an HDC material comprises an adhesion layer with apre-oxidized sidewall which impedes the adhesion layer from undergoingsubstantial oxidation and expansion during HDC material deposition.These structures may also be used for multilayer capacitors and otherthin-film devices such as pyroelectric devices (e.g. (uncooled) infrareddetectors), non-volatile ferroelectric RAMs (using permanentpolarization properties), thin-film piezoelectric and thin-filmelectro-optic devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asother features and advantages thereof, will be best understood byreference to the detailed description which follows, read in conjunctionwith the accompanying drawings, wherein:

FIGS. 1-4 are cross-sectional views showing the progressive steps in thefabrication of a high-dielectric constant material capacitor with anelectrode comprising a non-conductive, pre-oxidized sidewall; and

FIGS. 5-8 are cross-sectional views showing the progressive steps in thefabrication of a high-dielectric constant material capacitor with anelectrode comprising a conductive, pre-oxidized sidewall.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1-4, there is shown a method of forming anembodiment of the present invention, a lower electrode structurecomprising a preoxidized sidewall. FIG. 1 illustrates an SiO₂ layer 32overlying silicon semiconductor substrate 30. SiO₂ layer 32 may or maynot be capped with a diffusion barrier such as TiO₂ or Si₃ N₄. TiSi₂/poly-Si plug 34 provides electrical connection through SiO₂ layer 32. A100 nm TiN layer 36 has been reactively sputter deposited and patternedetched on the structure.

Various other standard processes can be used to form this portionstructure, such as sputter depositing Ti on poly-Si followed by an N₂rapid thermal anneal (700° C. for 30 seconds NH₃ furnace anneal (575° C.for 10 minutes). The TiN is then selectively removed chemically usingperoxide to form the patterned TiN layer 36 shown. In an alternatemethod, a vapor HF clean of the underlying poly-Si is performedimmediately prior to the deposition of TiN layers 36, without usingTiSi₂. It is beneficial that the structure not be exposed to acontaminating environment, such as the atmosphere, between the HF cleanand the adhesion layer deposition process steps, in order to ensure goodadhesion between the poly-Si and the TiN layer.

A 100 nm Pt layer 38 is then DC sputter deposited in a 5 mTorr Aratmosphere using a Pt target with the substrate temperature held at 325°C. Pt layer 38 can also be deposited using e-beam evaporation, chemicalvapor deposition (CVD), or metalorganic CVD (MOCVD). The height of Ptlayer 38 can vary depending on the desired capacitance density of theHDC material, the total desired capacitance, and the generation of thedevice. For example, future devices such as 1G DRAMs may generallyrequire taller capacitors to provide more electrode surface area/unitarea as compared to 256 DRAM devices, since 1G DRAMs will generally needto provide more capacitance/unit area (due to e.g. increasedfunctionality and shrinking device features). After deposition of Ptlayer 38, photoresist is deposited and patterned. Platinum layer 38 isthen dry etched in a low-pressure, high-density plasma reactive ion etch(RIE) reactor to form the structure shown in FIG. 1.

The structure is then annealed in a diluted oxygen (5% O₂ in N₂) gas at650° l C. to form TiO₂ sidewall 40 as shown in FIG. 2. The substantialdeformation of the structure. including Pt layer 38, occurs at thispoint, before deposition of the HDC material. Alternatively, ozone couldbe used for annealing. Alternatively, the structure could be annealed ata lower temperature (e.g. 600° C.), allowing Pt layer 38 more time torelax than if the oxidation is performed at full BST depositiontemperature. Another benefit of this oxidation anneal process is that Ptlayer 38 can rearrange to round any relatively sharp corners presentafter etching, since sharp corner can cause excess leakage current oreven cracks.

Then BST layer 42 is formed on the electrode structure using metalorganic chemical vapor deposition (MOCVD) at 650° C. in an O₂ /Ar (1/9)mixture gas at a pressure of 10 mTorr, resulting in the structure shownin FIG. 3. Substantial oxidation or expansion of the TiO₂ sidewalls doesnot occur during BST deposition, thus minimizing expansion stress andcracks in BST layer 42. The deposition may used ionic, photonic,electronic or plasma enhancement. BST layer 42 may also be formed byCVD, sputter or spin coat methods.

Upper Pt electrode 44 is them sputter deposited and dry etched to formthe capacitor structure shown in FIG. 4. This structure, with both lowerand upper electrodes, can again be annealed to improve the capacitorproperties.

With reference to FIGS. 5-8, there is shown a method of forming anotherembodiment of the present invention, a capacitor with a lower electrodecomprising conductive, pre-oxidized sidewalls. The structure illustratedin FIG. 5 is similar to the structure of FIG. 1, except that rutheniumis deposited for adhesion layer 46, instead of TiN. Since Ru has aconductive oxide, the surface of ruthenium layer 46 is oxidized to formRuO₂ layer 48, before deposition of Pt layer 38. In this embodiment,current will still be able to flow between substrate 30 and Pt layer 38even though the top surface of the adhesion layer has been oxidized.

The structure is then annealed in an oxygen containing atmosphere toform RuO₂ sidewall 50 as shown in FIG. 6. As with the previousembodiment, the substantial deformation of the structure, including Ptlayer 38, occurs at this point, before deposition of the HDC material.

Then BST layer 42 is formed on the electrode structure using MOCVD asdescribed hereinabove, resulting in the structure shown in FIG. 7.Again, substantial oxidation or expansion of the RuO₂ sidewalls does notoccur during BST deposition, thus minimizing expansion stress and cracksin BST layer 42. Upper Pt electrode 44 is them sputter deposited and dryetched to form the capacitor structure shown in FIG. 8.

One potential advantage of this embodiment is that the conductivesidewall structure of FIG. 8 generally allows more electrode surfacearea to be in contact with the HDC material as compared to thenon-conductive sidewall structure of FIG. 4.

Another potential advantage of this embodiment is that the top surfaceof Ru layer 46 is oxidized before the deposition of Pt layer 38, sofurther oxidation of the top surface of the Ru layer 46/RUO₂ layer 48 isminimized. The existing oxide limits the formation of irregular oxidizedareas on the top surface of the adhesion layer due to diffusion ofoxygen through Pt layer 38 (e.g. along pain boundaries), which can causehillocking of Pt layer 38.

The sole Table, below, provides an overview of some embodiments and thedrawings.

                  TABLE                                                           ______________________________________                                               Preferred or                                                           Drawing                                                                              Generic               Other Alternate                                  Element                                                                              Examples    Term      Examples                                         ______________________________________                                        30     Silicon     Substrate Other single component                                                        semiconductors                                                                (e.g. germanium, diamond)                                                     Compound                                                                      semiconductors (e.g.                                                          GaAs, InP, Si/Ge, SiC)                                                        Ceramic substrates                               32     Silicon dioxide                                                                           First level                                                                             Other insulators                                                    insulator (e.g. silicon nitride)                                                        Doped insudators                                                              (e.g. BSG, PSG, BPSG)                                                         May be more than                                                              one layer                                                                     (e.g. Si.sub.3 N.sub.4                                                        barrier over SiO.sub.2)                                                       May or may not                                                                be used (i.e. first                                                           level insulator,                                                              substrate, another                                                            insulating layer                                                              or a combination                                                              thereof may be                                                                the supporting                                                                layer for the                                                                 lower electrode)                                                              Combinations of                                                               the above materials                              34     TiSi.sub.2 /poly-Si                                                                       Conductive                                                                              Other metal                                                         plug      compounds                                                                     (e.g. nitrides:                                                               titanium nitride,                                                             zirconium nitride:                                                            silicides:                                                                    tantalum silicide,                                                            tungsten silicide,                                                            molybdenum silicide,                                                          nickel silicide;                                                              carbides: boron                                                               carbide,                                                                      tantalum carbide;                                                             borides:                                                                      titanium boride)                                                              Conductive metals                                                             (e.g. tungsten,                                                               tantalum,                                                                     titanium, molybdenum)                                                         Single component                                                              semiconductors                                                                (e.g. single- or                                                              poly-crystalline                                                              silicon, germanium)                                                           Compound                                                                      semiconductors                                                                (e.g. GaAs, InP,                                                              Si/Ge, SiC)                                                                   Other silicides                                                               may be used in a                                                              composite structure                                                           (Ni silicide,                                                                 Co silicide, tungsten                                                         silicide)                                                                     May be multiple                                                               layers (e.g.                                                                  TiN/TiSi.sub.x /poly-Si)                                                      Combinations of                                                               the above materials                              36     TiN         Adhesion  Other conductive                                                    layer     metal compounds                                  46     Ruthenium             (e.g. oxides:                                                                 ruthenium oxide,                                                              osmium oxide,                                                                 rhodium oxide,                                                                iridium oxide,                                                                indium oxide,                                                                 tin oxide)                                                                    Conductive metals                                                             (different from                                                               specific material                                                             selected for                                                                  drawing element                                                               38 below)                                                                     (e.g. tungsten,                                                               tantalum, titanium,                                                           tin, ruthenium,                                                               indium, osmium,                                                               rhodium, iridium)                                                             Ternary (or greater)                                                          amorphous nitrides                                                            (e.g. Ta--Si--N,                                                              Ti--Si--N, Ta--B--N,                                                          Ti--B--N)                                                                     Exotic conductive                                                             nitrides (e.g.                                                                titanium aluminum                                                             nitride, Zr nitride,                                                          Hf nitride, Y nitride,                                                        Sc nitride, La nitride and                                                    other rare earth nitrides,                                                    N deficient Al nitride,                                                       doped AI nitride,                                                             Mg nitride,                                                                   Ca nitride,                                                                   Sr nitride,                                                                   Ba nitride)                                                                   Alloys of the                                                                 above exotic                                                                  conductive nitrides                                                           with common Si                                                                processing materials                                                          such as TiN, GaN,                                                             Ni nitride, Co nitride,                                                       Ta nitride, W nitride                                                         (e.g. Ta--Al--N)                                                              Noble metal                                                                   insulator alloys                                                              (e.g. Pd--Si--N, Pr--Si--N,                                                   Pd--Si--O, Pd--Si--O,                                                         Pd--B--(O,N),                                                                 Pd--Al--N, Ru--Si--(O,N),                                                     Ir--Si--O, Re--Si--N,                                                         Rh--Al--O, Au--Si--N,                                                         Ag--Si--N)                                                                    May be multiple lavers                                                        (e.g. TiN/TiSi,                                                               TiN/TiSi/poly-Si)                                                             May be a layer                                                                having relatively                                                             better barrier properties                                                     over a layer having                                                           relatively better                                                             adhesive properties                                                           (e.g. Ru/TiN)                                                                 Combinations of                                                               the above materials                              38     Platinum    Noble metal                                                                             Other oxidation                                                     layer     resistant noble or                                                            platinum group metals                                                         (e.g. palladium,                                                              iridium, rhodium)                                                             Combinations of                                                               the above materials                                                           Layers of the                                                                 above materials                                  40     TiO.sub.2   Pre-Oxidized                                                                            Oxides formed                                                       sidewall  from materials                                                                used for drawing                                                              elements 36 and                                  50     RuO.sub.2             46 above (e.g. tantalum                                                       oxide, titanium oxide,                                                        tin oxide, indium                                                             oxide, iridium oxide,                                                         ruthenium oxide)                                                              Combinations of                                                               the above materials                              42     Barium      Hogh-     Other perovskite,                                       strontium   dielectric-                                                                             pyroelectric,                                           titanate    constant  ferroelectric or                                                    material  high-dielectric-                                                    layer     constant oxides                                                               (e.g. (Ba, Sr, Ca, Pb)                                                        (Ti, Zr)O.sub.3,                                                              (Pb, La)(Zr, Ti)O.sub.3,                                                      bismuth titanate,                                                             potassium tantalate,                                                          lead scandium tantalate,                                                      lead niobate,                                                                 potassium niobate,                                                            lead zinc niobate,                                                            lead magnesium niobate                                                        tantalum pentoxide,                                                           yttrium oxide)                                                                Donor, acceptor,                                                              or donor and                                                                  acceptor doped oxides                                                         listed above                                                                  Combinations of                                                               the above materials                                                           Layers of the                                                                 above materials.                                 44     Platinum    Upper     Conductive metal                                                    electrode compounds (e.g. nitrides:                                                     titanium nitride,                                                             ruthenium nitride,                                                            tin nitride,                                                                  zirconium nitride;                                                            oxides:                                                                       ruthenium dioxide,                                                            tin oxide,                                                                    titanium oxide,                                                               TiON, zinc oxide,                                                             doped zinc oxide,                                                             iridium oxide;                                                                silicides: titanium                                                           silicide, tantalum                                                            silicide, tungsten                                                            silicide, molybdenum                                                          silicide, nickel silicide;                                                    carbides: tantalum                                                            carbide; borides:                                                             titanium boride)                                                              Other noble or                                                                platinum group metals                                                         (e.g. palladium,                                                              ruthenium, rhodium,                                                           gold, iridium, silver)                                                        Reactive metals                                                               (e.g. tungsten, tantalum,                                                     titanium, molybdenum)                                                         Other common                                                                  semiconductor electrodes                                                      (e.g. aluminum,                                                               doped Si or Ge)                                                               Combinations of                                                               the above materials                                                           May contain more                                                              than one layer                                   48     RuO.sub.2   Conductive                                                                              Other conductive                                                    oxide layer                                                                             oxides (e.g. ruthenium                                                        oxide, osmium                                                                 oxide, rhodium                                                                oxide, iridium                                                                oxide, tin oxide,                                                             indium oxide)                                                                 Combinations of                                                               the above materials                              ______________________________________                                    

A few preferred embodiments have been described in detail hereinabove.It is to be understood that the scope of the invention also comprehendsembodiments different from those described, yet within the scope of theclaims. With reference to the structures described electricalconnections to such structures can be ohmic, rectifying, capacitive,direct or indirect, via intervening circuits or otherwise.Implementation is contemplated in discrete components or fullyintegrated circuits in silicon, germanium, gallium arsenide, or otherelectronic materials families. In general the preferred or specificexamples are preferred over the other alternate examples. The scale ofthe figures is neither to absolute nor relative scale; some thicknesseshave been exaggerated for clarity of explanation. Some components of thelower electrode may sometimes be referred to as being part of theelectrode and may sometimes be referred to as being interior to,exterior to, inside of, outside of, on, under, etc. the electrode; thestructures and methods of the present invention are substantially thesame in either case.

The adhesion layer may comprise other materials than those listed in thetable but which are generally less preferred than those materials in thetable. For example, the adhesion layer may comprise other metalcompounds such as ruthenium nitride, tin nitride, tungsten nitride,tantalum nitride, titanium oxide, TiON, titanium silicide, tantalumsilicide, tungsten silicide, molybdenum silicide, nickel silicide,cobalt silicide, iron silicide, chromium silicide, boron carbide,tantalum carbide, titanium carbide, zirconium carbide, titanium borideor zirconium boride. Alternatively, the adhesion layer may compriseother conductive metals (different from the specific material selectedfor drawing element 38) such as cobalt, iron, chromium, palladium,rhenium, zirconium, hafnium or molybdenum. Alternatively, the adhesionlayer may comprise single component semiconductors such as single- orpoly-crystalline silicon or germanium, or compound semiconductors suchas GaAs. InP, Si/Ge or SiC.

While this invention has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thedescription. It is therefore intended that the appended claims encompassany such modifications or embodiments.

What is claimed is:
 1. A microelectronic structure comprising:(a) asupporting layer having a principal surface; (b) an adhesion layeroverlying said principal surface of said supporting layer, said adhesionlayer comprising a top surface and an expanded, oxidized sidewall; (c) anoble metal layer overlying said top surface of said adhesion layer,said noble metal layer comprising a deformed area overlying saidoxidized sidewall; and (d) a high-dielectric-constant material layeroverlying said noble metal layer, whereby said high-dielectric-constantmaterial layer is substantially free of expansion stress cracks inproximity to said deformed area of said noble metal layer.
 2. Thestructure of claim 1, further comprising said high-dielectric-constantmaterial layer conformally overlying said oxidized sidewall of saidadhesion layer.
 3. The structure of claim 1, wherein said oxidizedsidewall comprises a conductive oxide.
 4. The structure of claim 3,wherein said adhesion layer comprises ruthenium and said oxidizedsidewall comprises ruthenium dioxide.
 5. The structure of claim 3wherein said top surface of said adhesion layer is oxidized.
 6. Thestructure of claim 5, wherein said adhesion layer comprises rutheniumand said oxidized sidewall comprises ruthenium dioxide.
 7. The structureof claim 1 further comprising an upper electrode overlying saidhigh-dielectric-constant material layer.
 8. The structure of claim 7,wherein said upper electrode is selected from the group consisting of:palladium, ruthenium, rhodium, gold, iridium, silver, and combinationsthereof.
 9. The structure of claim 1, wherein said oxidized sidewallcomprises an insulating oxide.
 10. The structure of claim 9, whereinsaid adhesion layer comprises titanium nitride and said insulating oxidecomprises titanium dioxide.
 11. The structure of claim 1, wherein saidadhesion layer is selected from the group consisting of: conductivemetals, conductive metal nitrides, conductive metal oxides, conductivemetal silicides, conductive metal carbides, conductive metal borides,ternary amorphous nitrides, and combinations thereof.
 12. The structureof claim 1, wherein said adhesion layer is selected from the groupconsisting of: titanium aluminum nitride, Zr nitride, Hf nitride, Ynitride, Sc nitride, La nitride, N deficient Al nitride, doped Alnitride, Mg nitride, Ca nitride, Sr nitride, Ba nitride, andcombinations thereof.
 13. The structure of claim 1, wherein saidhigh-dielectric-constant material layer is selected from the groupconsisting of: barium strontium titanate, lead zirconate titanate, leadlanthanum titanate, lead lanthanum zirconate titanate, bismuth titanate,potassium tantalate, lead scandium tantalate, lead niobate, lead zincniobate, potassium niobate, lead magnesium niobate, and combinationsthereof.
 14. The structure of claim 1, wherein said noble metal layer isselected from the group consisting of: platinum, palladium, iridium,rhodium, and combinations thereof.
 15. A microelectronic structurecomprising:(a) a supporting layer having a principal surface; (b) aconductive adhesion layer overlying said principal surface of saidsupporting layer, said adhesion layer comprising a top surface and anexpanded, conductive oxidized sidewall; (c) a noble metal layeroverlying said top surface of said adhesion layer, said noble metallayer comprising a deformed area overlying said oxidized sidewall; and(d) a high-dielectric-constant material layer overlying said noble metallayer, whereby said high-dielectric-constant material layer issubstantially free of expansion stress cracks in proximity to saiddeformed area of said noble metal layer.
 16. The structure of claim 15wherein said top surface of said adhesion layer is oxidized.
 17. Thestructure of claim 15, further comprising said high-dielectric-constantmaterial layer conformally overlying said oxidized sidewall of saidadhesion layer.
 18. A microelectronic capacitor comprising:(a) asupporting layer having a principal surface; (b) a ruthenium layeroverlying said principal surface of said supporting layer, saidruthenium layer comprising a top surface and an expanded, oxidizedsidewall; (c) a platinum layer overlying said top surface of saidruthenium layer; (d) a barium strontium titanate layer overlying saidplatinum layer; and (e) an upper electrode overlying said bariumstrontium titanate layer.